Filgrastim

Definition

Immunologic therapy is the treatment of disease using medicines that boost the body's natural immune response.

Purpose

Immunologic therapy is used to improve the immune system's natural ability to fight diseases such as cancer, hepatitis and AIDS. These drugs also may be used to help the body recover from the harmful side effects of treatments such as chemotherapy or radiation therapy.

Description

Most drugs in this category are artificially-made versions of substances produced naturally in the body. In their natural forms, these substances help defend the body against disease. For example, aldesleukin (Proleukin) is an artificially-made form of interleukin-2, which helps white blood cells work. Filgrastim (Neupogen) and sargramostim (Leukine) are versions of natural substances called colony stimulating factors, which encourage the bone marrow to make new white blood cells. Another type of drug, epoetin (Epogen, Procrit), stimulates the bone marrow to make new red blood cells. It is an artificially-made version of human erythropoietin, which is made naturally in the body and has the same effect on bone marrow. Thrombopoietin stimulates the production of platelets, disk-shaped bodies in the blood that are important in clotting. Interferons are substances the body produces to fight infections and tumors. Both natural and artificially made interferons are used to treat diseases.

Recommended dosage

The recommended dosage depends on the type of immunologic therapy. For some medicines, the physician will decide the dosage for each patient, taking into account the patient's weight and whether he or she is taking other medicines. Some drugs used in immunologic therapy are given only in a hospital, under a physician's supervision. For those that patients may give themselves, check with the physician who prescribed the medicine or the pharmacist who filled the prescription for the correct dosage.

Most of these drugs come in injectable form. Follow the instructions that come with the medicine for directions on how to prepare and inject it.

Precautions

Aldesleukin

This medicine may temporarily increase the chance of getting infections. It may also lower the number of platelets in the blood, which may interfere with the blood's ability to clot. Taking these precautions may reduce the chance of such problems:

• Avoid people with infections, if possible.
• Be alert to signs of infection, such as fever, chills, sore throat, pain in the lower back or side, cough, hoarseness, or painful or difficult urination. If any of these symptoms occur, get in touch with a physician immediately.
• Be alert to signs of bleeding problems, such as black, tarry stools, tiny red spots on the skin, blood in the urine or stools, or any other unusual bleeding or bruising.
• Take care to avoid cuts or other injuries. Be especially careful when using knives, razors, nail clippers and other sharp objects. Check with a dentist for the best ways to clean the teeth and mouth without injuring the gums. Do not have dental work done without checking with a physician.
• Wash the hands frequently, and avoid touching the eyes or inside of the nose unless the hands have just been washed.

Aldesleukin may make some medical conditions worse, such as chickenpox, shingles (herpes zoster), liver disease, lung disease, heart disease, underactive thyroid, psoriasis, immune system problems and mental problems. The medicine may increase the chance of seizures (convulsions) in people who are prone to having them. Also, the drug's effects may be greater in people with kidney disease, because their kidneys are slow to clear the medicine from their bodies.

Colony stimulating factors

Certain drugs used in treating cancer reduce the body's ability to fight infections. Although colony stimulating factors help restore the body's natural defenses, the process takes time. Getting prompt treatment for infections is important, even while taking this medicine. Call the physician at the first sign of illness or infection, such as a sore throat, fever or chills.

People with certain medical conditions may have problems if they take colony stimulating factors. In people who have kidney disease, liver disease or conditions caused by inflammation or immune system problems, colony stimulating factors may make these problems worse. People with heart disease may be more likely to have side effects such as water retention and heart rhythm problems when they take these drugs. And people with lung disease may be more likely to have shortness of breath. Anyone who has any of these medical conditions should check with his or her physician before using colony stimulating factors.

Epoetin

This medicine may cause seizures (convulsions), especially in people who are prone to having them. Noone who takes these drugs should drive, use machines or do anything else that might be dangerous if he or she has a seizure.

Epoetin helps the body make new red blood cells, but it cannot do its job unless there is plenty of iron in the body. The physician may recommend taking iron supplements or certain vitamins that help get iron into the body. Follow the physician's orders to make sure the body has enough iron for this medicine to work. Do not take iron supplements without a physician's consent.

In studies of laboratory animals, epoetin taken during pregnancy caused birth defects, including damage to the bones and spine. However, the drug has not been reported to cause problems in human babies whose mothers take it. Women who are pregnant or who may become pregnant should check with their physicians for the most up-to-date information on the safety of taking this medicine during pregnancy.

People with certain medical conditions may have problems if they take this medicine. For example, the chance of side effects may be greater in people with high blood pressure, heart or blood vessel disease or a history of blood clots. And epoetin may not work properly in people who have bone problems or sickle cell anemia.

Interferons

Interferons may add to the effects of alcohol and other drugs that slow down the central nervous system, such as antihistamines, cold medicine, allergy medicine, sleep aids, medicine for seizures, tranquilizers, some pain relievers, and muscle relaxants. They may also add to the effects of anesthetics, including those used for dental procedures. Anyone taking interferons should check with his or her physician before taking any of the above.

Some people feel dizzy, unusually tired or less alert than usual while being treated with these drugs. Because of these possible problems, anyone who takes these drugs should not drive, use machines or do anything else that might be dangerous until they have found out how the drugs affect them.

Interferons often cause flu-like symptoms, including fever and chills. The physician who prescribes this medicine may recommend taking acetaminophen (Tylenol) before--and sometimes after--each dose to keep the fever from getting too high. If the physician recommends this, follow his or her instructions carefully.

Like aldesleukin, interferons may temporarily increase the chance of getting infections and may lower the number of platelets in the blood, leading to clotting problems. To help prevent these problems, follow the precautions for reducing the risk of infection and bleeding listed for aldesleukin.

People who have certain medical conditions may have problems if they take interferons. For example, the drugs may worsen some medical conditions, including heart disease, kidney disease, liver disease, lung disease, diabetes, bleeding problems and mental problems. In people who have overactive immune systems, these drugs may make the immune system even more active. People who have shingles or chickenpox or who have recently been exposed to chickenpox may increase their risk of developing severe problems in other parts of the body if they take interferons. And people with a history of seizures or mental problems who take interferons may be at risk of having nervous system problems.

In teenage women, interferons may cause changes in the menstrual cycle. Young women should discuss this possibility with their physicians.

Older people may be more sensitive to the effects of interferons. This may increase the chance of side effects.

These drugs are not known to cause fetal death, birth defects or other problems in humans when taken during pregnancy. Women who are pregnant or who may become pregnant should ask their physicians for the latest information on the safety of taking these drugs during pregnancy.

Women who are breastfeeding their babies may need to stop while taking this medicine. Whether interferons pass into breast milk is not known, but because of the chance of serious side effects to the baby, breast-feeding while taking interferon is discouraged. Check with a physician for advice.

General precautions for all types of immunologic therapy

Seeing a physician regularly while being treated with immunologic therapy is important. This gives the physician a chance to make sure the medicine is working and to check for unwanted side effects.

Anyone who has had unusual reactions to drugs used in immunologic therapy should let his or her physician know before taking the drugs again. The physician should also be told about any allergies to foods, dyes, preservatives, or other substances.

Side effects

Aldesleukin

In addition to its helpful effects, this medicine may cause serious side effects. Generally, it is given only in a hospital, where medical professionals can watch for early signs of problems. They may also do some medical tests to check for unwanted effects.

Anyone who has breathing problems, fever or chills while being given aldesleukin should check with a physician immediately.

Other side effects should be brought to a physician's attention as soon as possible:

• Dizziness
• Drowsiness
• Confusion
• Agitation
• Depression
• Nausea and vomiting
• Diarrhea
• Sores in the mouth and on the lips
• Tingling of hands or feet
• Decrease in urination
• Weight gain of 5 or more pounds.

Some side effects are usually temporary and do not need medical attention unless they are bothersome. These include dry skin; itchy or burning skin rash or redness followed by peeling; loss of appetite; and a general feeling of illness or discomfort.

Colony stimulating factors

As this medicine starts to work, mild pain may be experienced in the lower back or hips. This is nothing to worry about, and it will usually go away within a few days. If the pain is too uncomfortable, the physician may prescribe a painkiller.

Other possible side effects include headache, joint or muscle pain and skin rash or itching. These side effects usually go away as the body adjusts to the medicine and do not need medical treatment. If they continue or they interfere with normal activities, check with a physician.

Epoetin

This medicine may cause flu-like symptoms, such as muscle aches, bone pain, fever, chills, shivering, and sweating, within a few hours after it is taken. These symptoms usually go away within 12 hours. If they do not, or if they are troubling, check with a physician. Other possible side effects that do not need medical attention are diarrhea, nausea or vomiting and tiredness or weakness.

Certain side effects should be brought to a physician's attention as soon as possible. These include headache, vision problems, increased blood pressure, fast heartbeat, weight gain and swelling of the face, fingers, lower legs, ankles or feet.

Anyone who has chest pain or seizures after taking epoetin should check with a physician immediately.

Interferons

This medicine may cause temporary hair loss. This may be upsetting, but it is not a sign that something is seriously wrong. The hair should grow back normally after treatment ends.

Many other side effects usually go away during treatment, as the body adjusts to the medicine. These include flu-like symptoms, changes in taste, loss of appetite, nausea and vomiting, skin rash, and unusual tiredness. If these problems do not go away or if they interfere with normal life, check with a physician.

A few more serious side effects should be brought to a physician's attention as soon as possible:

• Confusion
• Difficulty thinking or concentrating
• Nervousness
• Depression
• Sleep problems
• Numbness or tingling in the fingers, toes and face.

General advice on side effects for all types of immunologic therapy

Other side effects are possible with any type of immunologic therapy. Anyone who has unusual symptoms during or after treatment with these drugs should get in touch with his or her physician.

Interactions

Anyone who has immunologic therapy should let the physician know all other medicines he or she is taking. Some combinations of drugs may interact, that can increase or decrease the effects of one or both drugs or may make side effects more likely. Ask the physician whether the possible interactions can interfere with drug therapy or cause harmful effects.

Key Terms

AIDS

Acquired immunodeficiency syndrome. A disease caused by infection with the human immunodeficiency virus (HIV). In people with this disease, the immune system breaks down, opening the door to other infections and some types of cancer.

Bone marrow

Soft tissue that fills the hollow centers of bones. Blood cells and platelets (disk-shaped bodies in the blood that are important in clotting) are produced in the bone marrow.

Chemotherapy

Treatment of an illness with chemical agents. The term is usually used to describe the treatment of cancer with drugs.

Clot

A hard mass that forms when blood gels.

Fetus

A developing baby inside the womb.

Hepatitis

Inflammation of the liver caused by a virus, chemical or drug.

Immune response

The body's natural, protective reaction to disease and infection.

Immune system

The system that protects the body against disease and infection through immune responses.

Inflammation

Pain, redness, swelling, and heat that usually develop in response to injury or illness.

Psoriasis

A skin disease in which people have itchy, scaly, red patches on the skin.

Seizure

A sudden attack, spasm, or convulsion.

Shingles

An disease caused by an infection with the Herpes zoster virus, the same virus that causes chickenpox. Symptoms of shingles include pain and blisters along one nerve, usually on the face, chest, stomach, or back.

Sickle cell anemia

An inherited disorder in which red blood cells contain an abnormal form of hemoglobin, a protein that carries oxygen. The abnormal form of hemoglobin causes the red cells to become sickle-shaped. The misshapen cells may clog blood vessels, preventing oxygen from reaching tissues and leading to pain, blood clots and other problems. Sickle cell anemia is most common in people of African descent and in people from Italy, Greece, India, and the Middle East.

Further Reading

For Your Information

Periodicals

• Dale, David C. "Where now for colony-stimulating factors?"Lancet 346 (July 15, 1995): 135.
• Haynes, Barton F. "New frontiers of immunotherapy for HIV."Lancet 347 (December 7, 1996): 1531.
• Old, Lloyd J. "Immunotherapy for cancer." (Therapies of the Future)Scientific American 275 (September 1996): 136.
• Ward, Darrell E. "Taking advantage of the body's healing power."USA Today Magazine 123 (May 1995): 68.

Gale Encyclopedia of Medicine. Gale Research, 1999.